1. Field of the Invention
The present invention relates to a leakage check system for an enclosed liquid, like beer, sealed in a vessel, which, for example, can determine whether the enclosed liquid has leaked from a port of the vessel to remove such unacceptable vessels.
2. Prior Art
There has been a barrel-shaped vessel made of aluminum plates or steel plates for containing a liquid, like beer. The vessel has a comparatively large capacity and has a durable structure. The vessel has a capacity of 7, 10, 15, 20, 25, or 50 liters.
The vessel has a sealing valve unit for preventing a liquid enclosed in the vessel from deteriorating in its quality and taste. The valve unit has a generally cylindrical outlet port that can seal the liquid even after a cap of the outlet port is removed.
The sealing valve unit, for example, as shown in FIG. 9, includes a generally cylindrical outlet port 1'A mounted in an upper end plate of a vessel 1' that contains a sealed-in liquid N, like beer, a bush screwed into an inner threaded surface of the outlet port 1'A of the vessel 1' to be attached to the outlet port 1'A, a cylindrical member c inserted in the bush a and pre-loaded by a first spring b, a gas sealing valve d engageable with an upper inner surface of the bush a and provided on an upper, outer circumferential surface of the cylindrical member c, and a liquid valve f provided inside an upper part of the cylindrical member c and pre-loaded by a second spring e. Opening the gas sealing valve d feeds a pressurized gas G into the vessel 1', which pumps the enclosed liquid N through the cylindrical member c to deliver the liquid N outside of the vessel 1'. That is, the sealing valve unit 5' has two valves consisting of the gas sealing valve d and the liquid valve f.
In FIG. 12, there is disclosed another known sealing valve unit 5" having a bush a. The bush a has an outer circumferential threaded surface that is screwed in an inner circumferential threaded surface 1'Al of an outlet port 1'A of a vessel 1'. In the bush a, there is provided a valve V' having a flat surface F' pre-loaded by a spring b' for closing a gas passage s1 and a liquid passage s2.
In a beer production line, there has been a leakage check system for determining whether an enclosed liquid sealed within a vessel is leaking from its outlet port. Recently, a leaked vessel found by the check system is removed from the production line, and the enclosed liquid in the vessel is drawn out to be cost-effectively reused. The empty vessel tends to be recycled in view of a resources problem.
A known leakage check system is shown in FIGS. 10 and 11. A barrel-shaped vessel 1' is provided with a generally cylindrical outlet port 1'A with a sealing valve unit 5' at an upper portion thereof. The vessel 1' in an upright position (the outlet port 1'A is directed upward) is conveyed by a conveyor 2'. The system includes a well g defined in the outlet port 1'A, a water feeder 27' for supplying a predetermined quantity of a dilution water into the well g, an electrode 17' that is soaked in a dilution liquid W in the wall g for measuring the electrical conductivity of the liquid W, a mounting plate 22' for vertically downwardly supporting the electrode 17', and an actuator 20' such as a hydraulic cylinder device for moving up and down the mounting plate 22' connected thereto.
In a test for checking whether the enclosed liquid N in the vessel 1' has leaked from the outlet port 1'A to the outside, first, the vessel 1' that has been conveyed by the conveyor 2' stops at a water supply location Q' where a predetermined quantity of a dilution water W required for the leakage check is supplied from the water feeder 27' into the well g defined in the outlet port 1'A. Next, the vessel 1' having the outlet port 1'A, the well g of which has been filled with the dilution liquid W, is moved forward by the conveyor 2' and is stopped at a leakage check location K'. Then, the actuator 20' moves the electrode 17' in its axial direction T to soak the electrode 17' in the dilution liquid W. Thus, the measurement of the electrical conductivity of the dilution liquid W can recognize the presence of leakage of the enclosed liquid N. The leakage of the enclosed liquid N occurs due to an incomplete closing or a deterioration of the gas sealing valve d or the liquid valve f of the sealing valve unit 5'.
However, in the known leakage check system of the enclosed liquid shown in FIGS. 10 and 11, the vessel 1' necessarily has the well g that is defined in the outlet port 1'A for storing the predetermined quantity of the dilution liquid W so as to measure the electrical conductivity. Furthermore, in the leakage check system, the electrode 17', the actuator 20' for moving the electrode 17', and the water feeder 27' should be arranged above the vessel 1' since the vessel 1' is conveyed by the conveyor 2' in the upright position so that the outlet port 1'A is directed upward.
In the case of the vessel 1' shown in FIG. 12, there is not a well in the outlet port 1'A for storing a dilution liquid since the outlet port 1'A has the valve V' provided with the flat surface F' that is located at the top of the outlet port 1'A. This arrangement is different from the outlet port shown in FIG. 9, which can have the wall g above the sealing valve unit 5'.
Moreover, in the known leakage check system, a travel distance L' of the vessel 1' between the water supply location Q' and the leakage check location K' is comparatively long so that it disadvantageously requires an additional transfer operation of the vessel 1' for checking the leakage of the enclosed liquid N in the vessel 1'. Furthermore, the transfer operation of the vessel 1' on the conveyor 2' exerts on the vessel 1' a vibration force or an impactive force due to, for example, friction between the vessel 1' and a guide G1 provided on each side of the moving conveyor 2'. Thereby, the dilution liquid W contained in the outlet port 1'A possibly flows out to the outside, partially losing the predetermined quantity of the dilution liquid W for the leakage check. In addition, the dilution liquid W might be contaminated with dust or other undesirable substances, which does not allow a correct leakage check.
Moreover, the known leakage check system uses the dilution liquid W that is stored in the well g defined in the outlet port 1'A for checking the leakage of the enclosed liquid N. Where the vessel 1' has the sealing valve unit 5' that includes the gas sealing valve d and the liquid valve f in the outlet port 1'A, only the leakage of the enclosed liquid N through the gas sealing valve d and the liquid valve f can be checked. Thus, the leakage of the enclosed liquid N from an engagement surface of the sealing valve unit 5' with the outlet port 1'A can not be checked by the known leakage check system.
Meanwhile, when the vessel 1' in an upside-down position is conveyed by the conveyor 2', the well g of the outlet port 1'A can not store a dilution liquid W. Thus, the above-described leakage check system would not be able to check the leakage at all. In addition, the leakage check system also would not be able to check the leakage of the enclosed liquid N from the sealing valve unit 5" shown in FIG. 12, which has the flat surface F at the top thereof, even when the vessel 1' is in an upside-down position.
In view of the above-mentioned disadvantages, a basic object of the present invention is to provide a leakage check system for an enclosed liquid in a vessel, which can check the vessel that is in an upside-down position so that an outlet port of the vessel is directed downward when conveyed by a conveyor. Furthermore, the leakage check system would be able to check the leakage of the enclosed liquid even when the vessel does not have a well in the outlet port but has a flat surface in the outlet port. In addition, the system would be able to keep a predetermined quantity of a dilution liquid for checking the leakage correctly and effectively with reduced check time.